We recently established that the irradiation of A-homocholest-4a (5)-ene-3-one yield two isomeric photoproducts. The major product was shown to have a cis A/B ring junction while the minor product had a trans A/B junction. When substituents on the steroid nucleus were varied less of the minor isomer formed and in one case none was observed. In order for this reaction to be useful in a synthetic scheme it is important to better understand the factors that determine the stereochemistry of the photoproducts. We therefore are currently investigating the effect of solvent and temperature on the course of the rearrangement.